Pumping apparatus



April 18, 1950 v. J. MILL PUMPING APPARATUS 2 Sheets-Sheet l Flled April 12, 1945 EN TOR.

April 18, 1950 v. J. MILL PUMPING APPARATUS 2 Sheets-Sheet 2 Flled April l2, 1945 IN VEN TOR.

ATTORNEYS Patented Apr. 18, 1950 PUMPING APPARATUS Victor J. Mill, Lawrence, Masa, assignor to Lawrence Machine and Pump Corporation, Lawrence, Mass, a corporation of Massachusetts Application April 12, 1945, Serial No. 587,908

This invention relates to a pumping apparatus and more particularly to an apparatus of this character in which the pump is submerged in a liquid containing abrasive materials in suspension or liquids which are of a corrosive mixture.

One of the principal uses of this pump is for pumping slurry which may consist of a watery mixture of powdered raw materials for hydraulic cement.

One of the objects of this invention is to so organize the pump that the side pressure exerted by the movable elements against the liquid which is being pumped is balanced relative to the center of rotation of the movable elements and thereby avoid side thrust on the shaft whichsupports the movable pump element and the bearings in which this shaft is journaled.

Another object of this invention is to so mount the shaft of the pump on the cover of the tank containing the liquid material which is being pumped, that an effective seal is produced between the pump shaft and the top of the tank which will prevent the escape of any gases from the tank during the operation of the pump.

A further object of this invention is to provide means which will positively permit of efliciently journaling the impeller of the rotary pump on the top of the tank and still prevent the escape of any gases which may be generated in the tank upon agitating liquids of a corrosive character.

In the accompanying drawings:

Fig. 1 is a vertical section of a pumping apparatus embodying my invention and showing one form of means for preventing the escape of gas from the interior of the tank.

Fg. 2 is a horizontal section, on an enlarged scale, taken on line 2-1, Fig. 1.

Fig. 3 is a fragmentary sectional view, similar to Fig. 1, but showing an alternate form of the means for sealing the joint between the top of the tank and the impeller shaft for the purpose of preventing the escape of gases from the tank.

In the following description, similar characters of reference indicate like parts in the several figures of the drawings:

Although the tank which holds the liquid containing an abrasive in solution or the liquid which contains corrosive ingredients may be variously constructed, this tank may comprise a bottom iii, an upright side wall I l and a top or cover I 2 which is detachably connected at its outer edge with a flange l3 on the upper end of the tank body by means of bolts It or the like.

Within the lower part of this tank and submerged in the liquid therein is located the easing of a centrifugal pump which comprises an 1 Claim. (Cl. 103-103) the lower edge of the peripheral wall by means of screws l8 or the like, thereby forming a circular pressure chamber between these members of the casing.

On its upper side the upper head of the pump casing is provided centrally with a tubular upwardly projecting neck I! which is arranged concentrically with the axis of the casing.

The pump casing is suspended within the tank from the cover of the same by means of an upright tubular housing which is provided at its lower ends with an external flange II which is detachably connected by means of screws or bolts 22 with a flange 23 at the upper end 01' the casing neck l9 and this housing is detachably connected at; its upper end with the underside of the tank cover by means of bolts or screws 2 connecting an external flange 25 at the upper end of this housing with said tank cover.

The liquid to be propelled or lifted from the tank is admitted to the pump casing through an inlet opening 28 arranged centrally on the lower head of the pump casing, this inlet opening being surrounded by means of a downwardly flaring flange 21 which terminates close to the bottom of the tank so as to permit of vertically removing the entire contents of the tank by means of this pump.

On diametrically opposite sides of the peripheral wall of the pump casing the same is provided with a pair of outlet openings 28, 28 through which the liquid drawn into the casing through the central opening in the bottom thereof, is discharged from the pump casing. The peripheral wall of the pump casing is so constructed-that the same forms two volutes 29, 29, each of which is arranged circumferentially of the casing and has its rear end 30 arranged adjacent to the inner side of one of the outlet openings 28 and relatively close to the axis of the casing while its front end 3| is arranged on the outer side of the other outlet opening 28 and farther from the axis, as shown in Fig. 2.

The liquid discharged through these two outlets of the pump casing is carried to the exterior of the tank by means of two upright delivery conduits, each of which comprises a lower vertical tubular section 32 which extends upwardly from one of the outlet openings 28 of the pump casing, an intermediate tubular section 33 arranged within the tank and having its lower end connected with the upper end of the lower section 32 by means of bolts 34 passing through external flanges 3 ll, it arranged on the respective ends of these conduit sections. The upper end of the intermediate conduit section engages with the underside of the tank cover and communicates with an opening I1 therein. Above the tank cover is arranged the upper section II of the respective delivery conduit from which the liquid removed from the tank is delivered to the place where the same is required. This upper section of the intermediate delivery conduit section II engages with the upper side of the tank cover and communicates with the opening 01 therein. The intermediate and upper sections 83, SI of each liquid delivery conduit are secured to the lower and upper sides of the tank cover by means of bolts It passing through the tank cover and flanges 4|, 4| arings I2, 58 which receive the upper part of this shaft and rotatably support the same at one point immediately above the cover of the tank and at another point more remote from the cover. These bearings are preferably so constructed that they not only provide lateral support for the impeller shaft and the impeller carried thereby, but also support the impeller shaft and impeller against downward thrust. Various means may be provided for supporting the stationary members of the lower and upper bearings, such for ranged on the adjacent parts of the intermediate and upper conduit sections, as shown in Fig. 1.

For the purpose of producing a rigid structure and maintaining the parts in their proper relative position the upper end of the central neck I: of the pumping casing is connected by means of webs or arms 42 with the upper ends of the lower conduit sections 32, as shown in Fig. 1.

Within the pump casing is arranged the rotary impeller whereby the liquid to be pumped is drawn into the casing through the inlet in the lower head thereof and then thrown radially outward therein by centrifugal force and dis charged from the casing through the outlet openings in the peripheral wall thereof. Although this impeller may be variously constructed, the same preferably comprises a'lower disk 43 provided centrally around its axis with a liquid inlet opening an upper disk It provided centrally with an upwardly projecting hub 46 which. is arranged in the lower part of the upper neck I! of the casing, and a plurality of curved vanes or blades 41 arranged in an annular row in the space between the lower and upper disks of the example, as a standard which surrounds the upper part of the impeller shaft and is secured at its lower end to the cover of the tank.

Power for driving theimpeller shaft and impeller may be derived from any suitable source. such as an electric motor or the like, the shaft of which may be' connected by suitable drivin means or gearing with an intermediate shaft 55 having its lower end connected with the upper end of the impeller shaft by means of a coupling similar to that shown at 5B in Fig. 1.

When the parts of this pumping aparatus are in their operative position ready for use, only the upper parts of the impeller shaft 48 are engaged by the bearings 52, 53 and that part of the impeller shaft below the cover of the tank and the impeller mounted on the lower end of this shaft are suspended freely and rotate without contacting any part of the housing or any part on the liquid which is being pumped while being impeller and connected therewith. Upon rotating the impeller in the direction in which they present their convex surfaces foremost and in the direction in which the volutes of the casing gradually widen radially from the axis of the casing and impeller, as indicated by the arrowin Fig. 2, the liquid is drawn from the lower part of the tank upwardly into the central inlet of the pump casing, then forced radially outward in the casing and discharged through the outlet openings 28 in the peripheral wall of the casing and then forced upwardly through the delivery conduits and discharged above the top of the tank. 1

Rotation of the impeller for this purpose is accomplished. by means which include an upright impeller driving shaft 48 which has its lower part arranged in the housing 20 and they neck is of the casing and has its lower end connected with the hub of the impeller. This connection between the impeller and the driving shaft may be effected in any suitable manner but preferably by securing the hub of the impeller. between a downwardly facing shoulder 49 on this shaft engaging with the lower end of the impeller hub by a screw nut 50 applied to the lower end of the impeller shaft. The impeller is compelled to turn with the impeller shaft by means of a longitudinal key 5i interposed between these parts.

The impeller shaft has its upper part projecting above the top of the tank cover and is journaied so that it can rotate about a vertical axis but is incapable of moving vertically, thisbeing accomplished by means of upper and lower beardischarged through these outlet openings is equal.- ized due to the counterbalancing efiect of the impeller blades on the streams of liquid which are discharged through these two outlet openings. As a result the radial pressure of the impeller blades against these two streams of liquid is uniform and the impeller shaft is maintained in its central axial position without requiring bearings of any kind for supporting the same at or near its lower end, thereby avoiding the necessity of dismantling the pumping apparatus in order to gain access to such bearings as has been the case heretofore.

When pumping liquids which give off a ga that should be retained in the tank, for example, when pumping liquids containing a corrosive element, means are provided whereby a tight fit is produced between the cover of the tank and the impeller shaft so as to permit the latter to rotate freely and still prevent the escape of objectionable gases.

Various means may be provided for sealing the joint between the impeller shaft and the tank cover. As shown in Fig. i, this is accomplished by providing the cover of the tank with an annular cup 51 which is adapted to hold a sealing liquid such as water or oil and which is mounted on the tank cover around the adjacent part of the impeller shaft and having an open top, a tubular skirt 58 having its upper part secured to the impeller shaft and its lower part dipping into the sealing liquid in the sealing cup, and an annular lid 59 surrounding the tubular skirt and secured to the upper end of the sealing cup 51, as shown in Fig. 1.

Instead of employing a liquid seal between the cover of the liquid tank and the impeller shaft, the same results can be obtained b means of the stufiing-box, which is shown in Fig. 3, and which comprises a cup-shaped holder 60 arranged within the upper part of the housing and surrounding the adjacent part of the impeller shaft and secured to the tank cover, a tubular gland 6| arranged within the upper part of the stuffing cup and around the adjacent part of the impeller shaft and adapted to be drawn downwardly by means of adjusting screws 62 connecting the same with the stuffing cup, and an annular packing 63 interposed between the bottom of the stufllng cup and the lower end of the stuffing gland and surrounding the adjacent part of the impeller shaft.

. Upon tightening the screws 62, the packing 83 will be pressed tightly against the periphery of the impeller shaft and thus form a seal between the same which will prevent the escape of gas from the tank and still permit the impeller shaft to rotate freely.

As a whole this. pumping apparatus is very simple in construction and low in cost, the same is very eflicient in operation and due to the uniformity of the radial pressure exerted by the impeller against the liquid being pumped, it is possible to maintain this apparatus in good working condition with minimum servicing and cost of maintenance. r a

I claim as my invention:

Apparatus for pumping abrasive or corrosive liquids from a tank having an enclosing cover, comprising a centrifugal pump casing arranged in said tank near the bottom thereof with its axis vertically disposed, said pump casing having a horizontally disposed circular working chamber communicating with a downwardly directed central inlet and communicating with two opposite horizontally enlarging volutes leading to diametrically opposite outlets in the upper wall of said pump casing at the enlarged ends of said volutes, and said casin'g'also having an upwardly projecting tubular cylindrical neck communicating 0 with said working chamber, a circular, bladed centrifugal impeller arranged in said pump casing to rotate coaxially therein and having a cylindrical hub arranged in said neck, the maximum.

diameters of said impeller and hub being substantially less than the internal diameters of said working chamber and neck, respectively, whereby said impeller is free to move horizontally in said pump casing and is centered only by the balanced liquid pressures provided by said opposite volutes and outlets, a drive shaft secured coaxially to said hub and extending upwardly through said cover,

an upright tubular houslns surrounding said drive shaft in spaced relation thereto and secured at its lower end to said neck-and at its upper end to the under side of said cover, outlet pipes each secured at its lower end to the top wall of said pump casing around a corresponding one of said outlets and at its upper-end to the under side of said cover around an outlet opening therein, and said neck being formed to provide a pair of integral radial arms and secured at its outer end to a corresponding one of said outlet pipes.

VICTOR J. MILL.

REFERENCES crrnn The following references are of record in the file of this patent:

UNITED STATES m'rsn'rs 

